Pesticide delivery system

ABSTRACT

In one embodiment, the present invention relates to a pesticide delivery system, containing a continuous film having a thickness from about 1 μm to about 1,000 μm and noncontinuous areas having sizes less than about 100 μm, the continuous film containing a particulate material wherein at least 90% by weight of the particulate material has a particle size of about 10 microns or less, and a pest control agent at least partially coating the particulate material. In another embodiment, the present invention relates to a method of delivering a pest control agent to a target organism, involving the steps of applying to at least a portion of a surface of a plant an effective amount of finely divided particulate material at least partially coated with the pest control agent, the particulate material containing from about 25% to about 100% by weight of a heat treated particulate material, wherein the partially coated finely divided particulate material as applied permits an exchange of gases on the surface of the plant and the partially coated finely divided particulate material forms a continuous film over the portion of the plant surface to which it is applied, and a maximum average size of openings in the continuous film is less than about 100 μm.

FIELD OF THE INVENTION

The present invention is directed to a pesticide delivery system andimproved methods for enhancing the activity of pesticides by improvingdelivery to target organisms.

BACKGROUND OF THE INVENTION

Pests, from microbial pests to insect pests, destroy inordinate amountscrops. Improved methods for protecting plants from pests are thereforedesired since they would increase the amount and stability of foodproduction. However, pesticides can be difficult to apply, and expensiveto maintain after application. Applying toxicants as dry pesticidescalled dusts is not desirable because it leads to uncontrolled driftingof potentially dangerous chemicals. Applying toxicants in liquids aspesticidal sprays leads to less drifting than dust applications.Nevertheless, regardless of the formulation and application method, theefficacy of a toxicant primarily depends upon its delivery to the targetorganism.

Pesticidal sprays typically leave residues on plant surfaces. Theseresidues represent an inefficient manner for contact with insects andother pests. Poor pesticide delivery leads to sub-lethal doses ofpesticides. Often times, even with adequate spraying or delivery,residues from conventional pesticidal sprays delivered by a watercarrier alone do not provide a proper (e.g., lethal) dose to an insect.Efficacy of a pesticidal residue on a plant surface requires that theresidue remain on the surface long enough to contact a pest. Surfacessuch as leaves, bark, soil, and wood may undesirably absorb pesticideresidues and therefore lower the effectiveness thereof. In other words,pesticides loose their effectiveness when applied to sorptive surfacessince contact with pests is inhibited.

Moreover, pesticide application can result in reduced photosynthesis.Generally speaking, pesticide sprays cause a short-term and long-termreduction in the rate of CO₂ uptake (necessary for photosynthesis) andenhance leaf senescence. Thus, although plant survival may increase witha pesticide application, decreased transpiration and decreasedphotosynthesis undesirably occurs. Photosynthesis and transpiration inplants are positively linked in that a decrease in transpirationgenerally leads to a decrease in photosynthesis.

In perennial crop production such as tree fruit, flower buds for thesubsequent year are initiated while fruit are developing for the currentgrowing season. In practice, a plant may or may not produce flower budsfor the subsequent year. One of the many biochemical cues to developflower buds is the rate of photosynthesis and the availability ofphotosynthetically derived carbohydrates for flower bud development.

The availability of carbohydrates is limited by the photosyntheticcapacity of the plant and the pool of carbohydrates is partitionedbetween the competing carbohydrate needs of the woody tissue, leaftissue, developing flower buds and developing fruit. If photosynthesisis limited during the flower bud initiation period, flower budinitiation is reduced and fewer flowers are produced the followingseason. Reduced flower number results in reduced fruit number. In thesubsequent year, the tree has a reduced number of fruit and it developsexcessive numbers of flower buds because it lacks the competingdeveloping fruit when flower buds are initiated. The alternatingproduction of large and small numbers of fruit is an undesirablecondition known as “alternate bearing”.

A related problem to alternate bearing is called “excessive fruit drop”.Normal fruit drop occurs when, simultaneously, the fruit is developing,tree growth is occurring, and flower buds are being initiated.Photosynthetically derived carbohydrates become limiting to all thegrowing tissues at this time in the growing season and the plant abortsthe developing fruit, and limits the initiation of flower buds. Whenpesticide application deleteriously effects or diminishesphotosynthesis, fruit drop is excessive.

Particle carriers for pesticides are generally suitable for control ofsoil-borne pests. They are not frequently used for foliar control ofinsects on plants due to difficulties associated with sticking to thefoliage, impeding photosynthesis, and/or consequent susceptibility toremoval by wind, rain, or other disturbing forces. Particle carriers forplant protection are not necessarily efficient or economic in view ofthese difficulties.

SUMMARY OF THE INVENTION

The present invention provides a pesticide delivery system and improvedmethods of delivering pesticides to target organisms. The presentinvention provides methods of increasing the amount and/or effectivenessof a pesticide or other pest control agent delivered to a targetorganism compared to conventional methods. The present invention alsoprovides methods of delivering a pest control agent to a plant andsimultaneously increasing the photosynthesis (or at least notdiminishing the photosynthesis of the plant).

In one embodiment, the present invention relates to a pesticide deliverysystem, containing a continuous film having a thickness from about 1 μmto about 1,000 μm and noncontinuous areas having sizes less than about100 μm, the continuous film containing a particulate material wherein atleast 90% by weight of the particulate material has a particle size ofabout 10 microns or less, and a pest control agent at least partiallycoating the particulate material.

In another embodiment, the present invention relates to a method ofdelivering a pest control agent to a target organism, involving thesteps of applying to at least a portion of a surface of a plant aneffective amount of finely divided particulate material at leastpartially coated with the pest control agent, the particulate materialcontaining from about 25% to about 100% by weight of a heat treatedparticulate material, wherein the partially coated finely dividedparticulate material as applied permits an exchange of gases on thesurface of the plant and the partially coated finely divided particulatematerial forms a continuous film over the portion of the plant surfaceto which it is applied, and a maximum average size of openings in thecontinuous film is less than about 100 μm.

In yet another embodiment, the present invention relates to a method formaking a pest control film, involving the steps of combining a volatileliquid, a pest control agent, and a particulate material wherein atleast 90% by weight of the particulate material has a particle size ofabout 5 microns or less to form a slurry; applying the slurry to asubstrate; and permitting at least a portion of the volatile liquid ofthe slurry to evaporate thereby forming the pest control film comprisingpest control agent coated particulate material on the substrate, thepest control film containing from about 0.01% to about 10% by weight ofthe pest control agent and from about 90% to about 99.99% by weight ofthe particulate material, wherein the pest control film permits anexchange of gases between a horticultural substrate and the environment.

DETAILED DESCRIPTION OF THE INVENTION

This invention relates to pesticide delivery systems and methods ofdelivering pest control agents to target organisms. The methods mayinvolve applying particulate materials containing at least one pestcontrol agent, which may form a film, on a plant thereby increasing theeffects of the pest control agent. The deleterious effects of pests onthe plant are reduced or eliminated while photosynthesis is notdiminished.

Photosynthesis is a process by which photosynthetic plants utilize solarenergy to build carbohydrates and other organic molecules from carbondioxide and water. The conversion of carbon dioxide to such organicmolecules is generally referred to as carbon fixation or photosynthesis.The effects of enhanced photosynthesis are typically observed byincreased yields/productivity, e.g., increased fruit size or production(usually measured in weight/acre), improved color, increased solublesolids, e.g. sugar, acidity, etc., and reduced plant temperature.Non-diminished photosynthesis is typically observed by little or nochange in yields/productivity.

The substrates to which the present invention relates includehorticultural crops such as actively growing agricultural crops,fruiting agricultural crops, actively growing ornamental crops, fruitingornamental crops and the products thereof, and other surfaces pestsinfest such as man-made structures and stored grains/fruits/nuts/seeds.Specific examples include fruits, vegetables, trees, flowers, grasses,and landscape plants and ornamental plants. Particularly preferredplants include apple trees, pear treas, peach trees, plum trees, lemontrees, grapefruit trees, avocado trees, orange trees, apricot trees,walnut trees, raspberry plants, strawberry plants, blueberry plants,blackberry plants, bosenberry plants, corn, beans including soybeans,squash, tobacco, roses, violets, tulips, tomato plants, grape vines,pepper plants, wheat, barley, oats, rye, triticale, and hops. Man-madestructures include buildings, storage containers, dwellings made ofvarious materials such as plastics, wood, stone, cement, and metal.

The pesticide delivery systems of the present invention contain at leastone particulate material and at least one pest control agent. The pestcontrol agent at least partially coats the outside of the particulatematerial. In another embodiment, the pest control agent substantiallycoats the outside of the particulate material. In yet anotherembodiment, the pest control agent completely coats the outside of theparticulate material.

While not wishing to be bound by any theory, it is believed that sincethe particulate material readily adheres to target organisms, and sincethe pest control agent at least partially coats the particulate materialforming a continuous matrix, a relatively large amount of pest controlagent is delivered to the target organism.

For purposes of this invention, pest control agents are compounds thateffect the behavior or mortality of a target organism, such as apesticide. Pest control agents include pesticides, insecticides,acaracides, fungicides, bactericides, herbicides, antibiotics,antimicrobials, nemacides, rodenticides, entomopathogens, phermones,attractants, plant growth regulators, insect growth regulators,chemosterilants, microbial pest control agents, repellents, viruses,phagostimulents, and plant nutrients. Plant nutrients include nitrogen,magnesium, calcium, boron, potassium, copper, iron, phosphorus,manganese, and zinc. Specific examples of these pesticides are known tothose skilled in the art, and many are readily commercially available.

Target organisms are susceptible to behavior modification and/orphysical debilitation due to exposure to a pesticide or pest controlagent. Target organisms range from bacteria to arthropods to microbes toplants. For example, target organisms include bacteria, fungus, wormsincluding nematodes, insects, arachnids such as spiders and mites,birds, rodents, deer, rabbit, and undesirable vegetation (weeds).

In some embodiments, two or more pest control agents are employed in thepesticide delivery systems of the present invention. For example, apesticide delivery system may contain an insecticide and a phermone orother attractant. In this instance, an attract and kill mechanism isemployed. The pest control agent partially, substantially or entirelycoats the outside of the particulate material. In other words, the pestcontrol agent need not entirely coat the outside of the particulatematerial. In some instances, it is preferable that the pest controlagent partially coat the outside of the particulate material, as theexposed regions of the particulate material may enhance secureattachment to a target organism. In other instances, it is preferablethat the pest control agent substantially or entirely coat the outsideof the particulate material, as the pest control agent, especially inthe case of an oil based pesticide, securely attach to a targetorganism.

In one embodiment, the particulate materials suitable for use in thepresent invention are highly reflective. As used herein, “highlyreflective” means a material having a “Block Brightness” of at leastabout 80 and preferably at least about 90 and more preferably at leastabout 95 as measured by TAPPI standard T 452. Measurements can be madeon a Reflectance Meter Technidyne S-4 Brightness Tester manufactured byTechnidyne Corporation which is calibrated at intervals not greater than60 days using brightness standards (paper tabs and opal glass standards)supplied by the Institute of Paper Science or Technidyne Corporation.Typically a particle block or plaque is prepared from 12 grams of a dry(<1% free moisture) powder. The sample is loosely placed in a cylinderholder and a plunger is slowly lowered over the sample to a pressure of29.5-30.5 psi and held for about 5 seconds. The pressure is released andthe plaque is examined for defects. A total of three plaques areprepared and three brightness values are recorded on each plaque byrotating the plaque about 120 degrees between readings. The nine valuesare than averaged and reported.

In one embodiment, the particulate materials suitable for use in thepresent invention are heat treated particulate materials. For purposesof this invention, heat treated particulate materials are particulatematerials that are heated to an elevated temperature and include bakedparticulate materials, dehydrated particulate materials, calcinedparticulate materials, and fired particulate materials. Heat treatedparticulate materials may be hydrophobic. Specific examples includecalcined calcium carbonate, calcined talc, calcined kaolin, bakedkaolin, fired kaolin, metakaolin, calcined bentonites, calcined clays,calcined pyrophyllite, calcined silica, calcined feldspar, calcinedsand, calcined quartz, calcined chalk, calcined limestone, calcinedprecipitated calcium carbonate, baked calcium carbonate, calcineddiatomaceous earth, calcined barytes, calcined aluminum trihydrate,calcined pyrogenic silica, calcined titanium dioxide dehydrated kaolin,dehydrated calcium carbonate, dehydrated bentonites, and dehydratedlimestone.

Heat treatment in accordance with the invention involves heating aparticulate material at a temperature from about 300° C. to about 1,200°C. for about 10 seconds to about 24 hours. In a preferred embodiment,heat treatment involves heating a particulate material at a temperaturefrom about 400° C. to about 1,100° C. for about 1 minute to about 15hours. In a more preferred embodiment, heat treatment involves heating aparticulate material at a temperature from about 500° C. to about 1,000°C. for about 10 minutes to about 10 hours. The heat treatment may becarried out in air, in an inert atmosphere or under a vacuum.

In most embodiments, the particulate materials contain at least about25% by weight, and particularly about 25% to about 100% by weight ofheat treated particulate materials. In another embodiment, theparticulate materials contain at least about 40% by weight, andparticularly about 40% to about 99% by weight of heat treatedparticulate materials. In yet another embodiment, the particulatematerials contain at least about 60% by weight, and particularly about60% to about 95% by weight of heat treated particulate materials. Instill yet another embodiment, the particulate materials contain at leastabout 70% by weight, and particularly about 70% to about 90% by weightof heat treated particulate materials.

In one embodiment, the heat treated particulate material comprises aheat treated kaolin, such as a metakaolin and/or a calcined kaolin. Inanother embodiment, the heat treated particulate material comprises ahydrophobic treated heat treated kaolin. Examples of preferred heattreated particulate materials that are commercially available fromEngelhard Corporation, Iselin, N.J. are the metakaolins sold under thetrade designation MetaMax, the calcined kaolins sold under the trademarkSatintone® and the siloxane treated calcined kaolins sold under thetrade designations Surround™ and Translink®.

In one embodiment, the particulate material is hydrophobic. In anotherembodiment, the particulate material is hydrophilic. In yet anotherembodiment, the particulate material contains hydrophobic materials andhydrophilic materials.

In addition to the heat treated particulate materials, the particulatematerials may optionally further include supplemental particulatematerials such as hydrophilic or hydrophobic materials and thehydrophobic materials may be hydrophobic in and of themselves, e.g.,mineral talc, or may be hydrophilic materials that are renderedhydrophobic by application of an outer coating of a suitable hydrophobicwetting agent (e.g., the particulate material has a hydrophilic core anda hydrophobic outer surface).

In one embodiment, the particulate materials contain about 1% to about75% by weight of supplemental particulate materials. In anotherembodiment, the particulate materials contain about 5% to about 60% byweight of supplemental particulate materials. In yet another embodiment,the particulate materials contain about 10% to about 30% by weight ofsupplemental particulate materials.

Typical supplemental particulate hydrophilic materials suitable for usein the present invention include: minerals, such as calcium carbonate,talc, hydrous kaolins, bentonites, pyrophyllite, silica, feldspar, sand,quartz, chalk, limestone, precipitated calcium carbonate, diatomaceousearth and barytes; functional fillers such as aluminum trihydrate,pyrogenic silica, sulfur, and titanium dioxide.

The surfaces of hydrophobic supplemental or heat treated materials canbe made hydrophobic by contact with hydrophobic wetting agents. Manyindustrial mineral applications, especially in organic systems such asplastic composites, films, organic coatings or rubbers, are dependentupon just such surface treatments to render the mineral surfacehydrophobic; see, for example, Jesse Edenbaum, Plastics Additives andModifiers Handbook, Van Nostrand Reinhold, New York, 1992, pages 497-500which is incorporated herein by reference for teachings of such surfacetreatment materials and their application. So-called coupling agentssuch as fatty acids and silanes are commonly used to surface treat solidparticles as fillers or additives targeted to these industries. Suchhydrophobic agents are well known in the art and common examplesinclude: organic titanates such as Tilcom® obtained from TioxideChemicals; organic zirconate or aluminate coupling agents obtained fromKenrich Petrochemical, Inc.; organofunctional silanes such as Silquest®products obtained from Witco or Prosil® products obtained from PCR;modified silicone fluids such as the DM-Fluids obtained from Shin Etsu;and fatty acids such as Hystrene® or Industrene® products obtained fromWitco Corporation or Emersol® products obtained from Henkel Corporation(stearic acid and stearate salts are particularly effective fatty acidsand salts thereof for rendering a particle surface hydrophobic).

Examples of preferred supplemental particulate materials that arecommercially available include calcium carbonate commercially availablefrom English China Clay under the trademarks Atomite® and Supermite® andstearic acid treated ground calcium carbonates commercially availablefrom English China Clay under the trademarks Supercoat® and Kotamite®.

In one embodiment, the particulate materials and/or pesticide deliverysystems of the present invention do not include calcium hydroxide. Inanother embodiment, the particulate materials and/or pesticide deliverysystems of the present invention do not include starch. In yet anotherembodiment, the particulate materials and/or pesticide delivery systemsof the present invention do not include hydrous kaolin. In still yetanother embodiment, the particulate materials and/or pesticide deliverysystems of the present invention do not include silica.

The term “finely divided” when utilized herein with the term“particulate materials” means that the particulate materials have amedian individual particle size below about 10 microns and preferablybelow about 3 microns and more preferably the median particle size isabout 1 micron or less, and even more preferably the median particlesize is about 0.5 microns or less.

Particle size and particle size distribution as used herein are measuredwith a Micromeritics Sedigraph 5100 Particle Size Analyzer. Measurementswere recorded in deionized water for hydrophilic particles. Dispersionswere prepared by weighing 4 grams of dry sample into a plastic beakeradding dispersant and diluting to the 80 ml mark with deionized water.The slurries were then stirred and set in an ultrasonic bath for 290seconds. Typically, for calcined kaolin 0.5% tetrasodium pyrophosphateis used as a dispersant; with calcined calcium carbonate 1.0% Calgon Tis used. Typical densities for the various powders are programmed intothe sedigraph, e.g., 2.58 g/ml for kaolin. The sample cells are filledwith the sample slurries and the X-rays are recorded and converted toparticle size distribution curves by the Stokes equation. The medianparticle size is determined at the 50% level.

In one embodiment, the particulate material has a particle sizedistribution wherein at least 90% by weight of the particles have aparticle size of under about 10 microns. In another embodiment, theparticulate material has a particle size distribution wherein at least90% by weight of the particles have a particle size of below about 3microns. In a preferred embodiment, the particulate material has aparticle size distribution wherein at least 90% by weight of theparticles have a particle size of about one micron or less. In still yetanother embodiment, the particulate material has a particle sizedistribution wherein at least 90% by weight of the particles have aparticle size of below about 0.5 microns. In this connection, theparticulate material according to the present invention has a relativelynarrow particle size distribution.

The particulate materials particularly suitable for use in thisinvention are inert and have low toxicity. As used herein, “inert”particulate materials are particles that are not phytotoxic. Theparticulate materials preferably have extremely low toxicity meaningthat in the quantities needed for effective enhanced horticulturaleffects, the particulate materials are not considered harmful toanimals, the environment, the applicator and the ultimate consumer.However, the pest control agent may or may not be characterized as inertand having low toxicity. Thus, while the particulate materials may beinert, the pesticide delivery system may or may not be characterized asinert and having low toxicity. Also as used herein, “inert” particulatematerials are particles that do not decompose the pest control agent.

The present invention further relates to treated substrates such ashorticultural crops wherein the surface of the plant is treated with thepesticide delivery system containing one or more particulate materials.This treatment should not materially affect the exchange of gases on thesurface of the plant. The gases which pass through the pesticidedelivery system treatment are those which are typically exchangedthrough the surface skin of living plants. Such gases typically includewater vapor, carbon dioxide, oxygen, nitrogen and volatile organics.

The surface of a plant, such as a horticultural crop, is treated with anamount of the pesticide delivery system containing one or more highlyreflective, finely divided particulate materials and one or more pestcontrol agents that is effective in reducing or eliminating a targetorganism without diminishing photosynthesis of the plant. The extent oftreatment coverage of a plant can be determined by one skilled in theart. Full coverage is preferred. Full coverage of areas where contactwith the target organism is likely is also preferred. Less than fullplant coverage is within the scope of this invention and can be highlyeffective, for example, neither the under surface of the plant (thatwhich is not frequently contacted by some target organisms) need betreated by the method of this invention nor must the upper surface ofthe plant be completely covered; although full or substantially fullplant substrate coverage is preferred. Particularly, full orsubstantially full fruit (or area where protection is desired) coverageis preferred, as other areas of a plant do not require such treatment.Full or substantially full plant substrate coverage can provideadditional benefits such as effective disease control, smoother fruitsurface, reduced bark and fruit cracking, and reduced russeting. Themethod of the present invention may result in a residue of the treatmentforming a membrane of one or more layers of the pesticide deliverysystem containing the highly reflective particulate materials andpesticide on the plant surface.

The pesticide delivery system suitable for use in the present inventionmay be applied as a slurry of finely divided particulate materials inone or more volatile liquids such as water, a low boiling organicsolvent or low boiling organic solvent/water mixture. In a preferredembodiment, the pest control agent is at least partially soluble in thevolatile liquid.

The low boiling organic liquids useful in the present invention arepreferably water-miscible and contain from 1 to about 6 carbon atoms.The term “low boiling” as used herein shall mean organic liquids whichhave a boiling point generally no more than about 100° C. These liquidscontribute to the ability of the pesticide delivery system to remain infinely divided form without significant agglomeration. Such low boilingorganic liquids are exemplified by: alcohols such as methanol, ethanol,propanol, i-propanol, i-butanol, and the like, ketones such as acetone,methyl ethyl ketone and the like, and cyclic ethers such as ethyleneoxide, propylene oxide and tetrahydrofuran. Combinations of theabove-mentioned liquids can also be employed. Methanol is the preferredlow boiling organic liquid.

Low boiling organic liquids may be employed in applying the pesticidedelivery system to plant substrates for the purposes of this invention.Typically, the liquids are used in an amount sufficient to form adispersion of the pesticide delivery system. The amount of low boilingorganic liquid is typically up to about 30 volume percent of thedispersion, preferably from about 1 to about 20 volume percent,preferably from about 3 to about 5 volume percent, and most preferablyfrom about 3.5 to about 4.5 volume percent. The pesticide deliverysystem is preferably added to a low boiling organic liquid to form aslurry and then this slurry is diluted with water to form an aqueousdispersion. The resulting slurry retains the pesticide delivery systemin finely divided form.

In one embodiment, the slurry contains from about 0.5% to about 50% byweight solids (particulate materials), less than about 5% by weight pestcontrol agent, and from about 70% to about 99.5% by weight of a volatileliquid. In another embodiment, the slurry contains from about 1% toabout 25% by weight solids (particulate materials), less than about 2%by weight pest control agent, and from about 75% to about 99% by weightof a volatile liquid. In yet another embodiment, the slurry containsfrom about 2% to about 15% by weight solids (particulate materials),less than about 1% by weight pest control agent, and from about 85% toabout 98% by weight of a volatile liquid.

Adjuvants such as surfactants, dispersants, speaders/stickers(adhesives), wetting agents, antifoaming agents, and/or drift reducingagents may be incorporated in preparing an aqueous slurry of thepesticide delivery system of this invention. In one embodiment, theslurry of the pesticide delivery system consists essentially of theparticulate materials, one or more pest control agents, and water andoptionally at least one of supplemental particulate materials, lowboiling organic solvents, surfactants, dispersants, spreaders/stickers,wetting agents, antifoaming agents, and drift reducing agents.

Surfactants and dispersants include nonionic surfactants, anionicsurfactants, cationic surfactants and/or amphoteric surfactants andpromote the ability of the aggregates to remain in solution duringspraying (contribute to a better quality slurry). Surfactants anddispersants also function to break-up agglomerates of particulatematerials.

Spreaders/stickers promote the ability of the pesticide delivery systemto adhere to plant surfaces. Wetting agents reduce surface tension ofwater in the slurry and thus increase the surface area over which agiven amount of the slurry may be applied. Antifoaming agents decreasesfoaming during spraying. Drift reducing agents prevent droplets frombecoming too small thus reducing the ability of slurry droplets to driftduring spraying.

One or more layers of the slurry can be sprayed or otherwise applied tothe plant surface. The volatile liquid is preferably allowed toevaporate between coatings. The residue of this treatment may behydrophilic or hydrophobic. Applying particles as a dust or brushing,although not being commercially practical on a large scale due to drift,inhalation hazards and poor residuality, is an alternative for carryingout the method of this invention. Spraying is a preferred method ofapplication.

Spreader/stickers that can be mixed with hydrophilic particles (0.5% ormore solids in water) to aid in spraying uniform treatments on a plantor horticultural substrate are, for example, modified phthalic glycerolalkyd resins such as Latron B-1956 from Rohm & Haas Co.; plant oil basedmaterials (cocodithalymide) with emulsifiers; polymeric terpenes;nonionic detergents (ethoxylated tall oil fatty acids); guar gum;xanthane gum, latex, agar, starch, and the like. In another embodiment,the amount of adjuvants in the aqueous slurry of the pesticide deliverysystem is from about 0.001% by weight to about 20% by weight. In yetanother embodiment, the amount of adjuvants in the aqueous slurry of thepesticide delivery system is from about 0.01% by weight to about 10% byweight. In still yet another embodiment, the amount of adjuvants in theaqueous slurry of the pesticide delivery system is from about 0.1% byweight to about 5% by weight.

The pesticide treatment may be applied as one or more layers of a matrixof finely divided particulate materials/pest control agent. The amountof material applied is within the skill of one of ordinary skill in theart. The amount will be sufficient to protect plants, structures, andgrains from target organism pests, and in the case of plants, withoutdiminishing photosynthesis of the plant to which these particles areapplied. For example, this can be accomplished by applying from about 25up to about 5000 micrograms of pesticide delivery system/cm² of plantsurface for particulate materials having specific density of around 2-3g/cm³, more typically from about 100 up to about 3000 micrograms ofpesticide delivery system/cm² of plant surface for particulate materialshaving specific density of around 2-3 g/cm³, and preferably from about100 up to about 500 micrograms of pesticide delivery system/cm² of plantsurface for particulate materials having specific density of around 2-3g/cm³. In addition, environmental conditions such as wind and rain mayreduce plant coverage of the pesticide delivery system and therefore itis within the scope of this invention to apply the pesticide deliverysystem one or more times during the growing season of said horticulturalplant so as to maintain the desired effect of invention.

After the slurry is applied to a substrate, the slurry is permitted todry (the volatile liquids evaporate) wherein a continuous orsubstantially continuous film of the particulate materials is formed. Bycontinuous, it is meant that, where applied, the dry film is continuous(or substantially continuous). For example, in an embodiment where theupper third of a fruit is covered with particulate material inaccordance with the present invention, the film covering the upper thirdof the fruit is continuous or substantially continuous while the bottomtwo-thirds of the fruit is not covered with the particulate material.

Of the covered portion of a substrate surface, the pesticide deliveryfilm is continuous in that it covers from about 75% to about 100% of thesurface area, thus the openings or noncontinuous areas the pesticidedelivery film constitutes from about 0% to about 25% of the surfacearea. In another embodiment, the pesticide delivery film is continuousin that it covers from about 90% to about 99.9% of the surface area,thus the openings or noncontinuous areas the pesticide delivery filmconstitutes from about 0.1% to about 10% of the surface area. In yetanother embodiment, the pesticide delivery film is continuous in that itcovers from about 95% to about 99% of the surface area, thus theopenings or noncontinuous areas the pesticide delivery film constitutesfrom about 5% to about 1% of the surface area.

In the continuous film, the maximum average size (average diameter) ofpores or noncontinuous areas in the pesticide delivery film is generallyless than about 100 μm. In another embodiment, the maximum average sizeof openings or noncontinuous areas in the pesticide delivery film isgenerally less than about 10 μm. In yet another embodiment, the maximumaverage size of openings or noncontinuous areas in the pesticidedelivery film is generally less than about 5 μm.

The thickness of the pesticide delivery film applied using a slurryranges from about 1 μm to about 1,000 μm. In another embodiment, thethickness of the pesticide delivery film ranges from about 3 μm to about750 μm. In yet another embodiment, the thickness of the pesticidedelivery film ranges from about 5 μm to about 500 μm.

In one embodiment, the pesticide delivery film contains from about 0.01%to about 30% by weight of a pest control agent and from about 70% toabout 99.99% by weight of a particulate material at least partiallycoated by the pest control agent. In another embodiment, the pesticidedelivery film contains from about 0.05% to about 10% by weight of a pestcontrol agent and from about 90% to about 99.95% by weight of aparticulate material. In yet another embodiment, the pesticide deliveryfilm contains from about 0.1% to about 5% by weight of a pest controlagent and from about 95% to about 99.9% by weight of a particulatematerial.

The amount of the pesticide delivery system applied varies dependingupon a number of factors including the manner of application, theidentity of the substrate, the amount of plants per acre and theconcentration of the particulate material and pest control agent in theslurry. Typically, the use rate of the pesticide delivery system appliedis from about 10 gallons/acre to about 1,000 gallons per acre (where theconcentration of the particulate material/pest control agent in theslurry is about 6% by weight solids).

Although continuous, the pesticide delivery film permits the exchange ofgases (water and carbon dioxide transpiration and photosynthesis,respectively) on the portions of the surface of a plant to which it isapplied. In this connection, the continuous pesticide delivery film isgas permeable or porous, but not discontinuous.

Moreover, since the target organism is partially covered in a matrix ofthe pesticide delivery film of the present invention, grooming andingestion by the target organism either spreads the pest control agentover the surface of the organism (thereby maximizing contact area), orintroduces the pest control agent into the internal organs/system of thepest. Both of these pathways enhance the behavior or mortality of thetarget organism by the pest control agent. Since the pesticide deliverysystem of the present invention effectively sticks to target organisms,a previously ineffective dosage of pest control agent (not used with theparticulate materials of the present invention) becomes an effectivelethal dose as the same amount of pest control agent is more efficientlyused by the present invention compared to conventional systems/methods.

The pesticide delivery film formed in accordance with the presentinvention effectively blocks (absorbs, scatters and/or reflects away)excessive UV and/or IR radiation that has damaging effects on planttissue and the pest control agent. In one embodiment, the pesticidedelivery film formed in accordance with the present invention blocks(absorbs, scatters and/or reflects away) from about 1% to about 10% ofthe UV and/or IR radiation to which it is exposed. In anotherembodiment, the pesticide delivery film formed in accordance with thepresent invention blocks from about 2% to about 5% of the UV and/or IRradiation to which it is exposed. As a result, the photosynthetic andbiochemical mechanisms of plants are not damaged or impeded by UV and/orIR radiation. The present invention in this embodiment provides a methodthat reduces UV and/or IR radiation at the plant surface that in turnreduces the environmental stress and increases photosynthesis. In manyinstances, reductions in UV and/or IR radiation reduces the degradationof a pest control agent; thus, the pesticide delivery system of thepresent invention extends the effectiveness or enhances the effects of apest control agent over a longer period of time.

The pesticide delivery film formed in accordance with the presentinvention can be readily and easily removed from substrates which are sotreated. In one embodiment, the pesticide delivery film can be andeasily removed from treated surfaces using a high pressure watersprayer, wherein the water contains or does not contain a suitablesurfactant. The identity of the surfactant depends upon the specificidentity of the pesticide delivery system, whether or not any adjuvantsare present, and the amount of any adjuvant, if any. In anotherembodiment, the pesticide delivery film can be and easily removed fromplants or fruits using a water bath or water spray, wherein the watercontains or does not contain a suitable surfactant, and optionallybrushing the plant or fruit.

Although the pesticide delivery system can be applied over plants, thesystem does not materially effect, and in most instances, does notdiminish the photosynthesis of the plants. In other words, contrary toconventional pesticide treatments that attempt to reduce populations oftarget organisms while undesirably diminishing photosynthesis, thepresent invention provides a pesticide delivery system that is appliedover plants to reduce populations of target organisms while notdiminishing photosynthesis. In one embodiment, application of thepesticide delivery system in accordance with the present inventionenhances the photosynthesis of the treated plants.

The following examples illustrate the present invention. Unlessotherwise indicated in the following examples and elsewhere in thespecification and claims, all parts and percentages are by weight, alltemperatures are in degrees Centigrade, and pressure is at or nearatmospheric pressure.

EXAMPLE 1

The enhanced effect of reducing fireblight in apple trees with thepesticide delivery system of the present invention containingbactericides is examined and compared to conventional pesticides.

Experiments are conducted on potted trees of ‘Rome’ apple in a naturallyilluminated greenhouse. When about 80% of the blooms are open, openblossoms are sprayed to drip with 10⁸ CFU of Erwinia amylovora (Ea)strain AFRS-581. After drying for about 1 hour, each the followingtreatments are applied to six of the infected trees. Slurries containingparticulate materials (PM) (3% weight by volume), water and copperhydroxide at 0.5 g/l (Copper Count N from Mineral Research DevelopmentCo., Charlotte, N.C., a bactericide), Blight Ban at 1 g/l (from PlantHealth Technologies, Boise, Id., a microbial bactericide), orstreptomycin at 0.5 g/l (from Novartis Crop Protection Inc., Greensboro,N.C., an antibiotic); and slurries containing PM (3% weight by volume)and water; and mixtures of water and copper hydroxide at 0.5 g/l, BlightBan at 1 g/l, or streptomycin at 0.5 g/l are applied to the apple trees.In Example 1 and Example 2 (below), the particulate material isSurround™ WP available from Engelhard Corporation, Iselin, N.J., whichis a calcined kaolin with an organic spreader/sticker.

After 7 days, blossom necrosis symptoms are present and recorded.Disease data are expressed as percentage of blossom infect rate. Table 1lists the data.

TABLE 1 Treatment % Blossom Infection PM 71.1 copper hydroxide 87.1Blight Ban 82.4 streptomycin 83.3 PM/copper hydroxide 60.2 PM/Blight Ban46.3 PM/streptomycin 44.2

EXAMPLE 2

The enhanced activity of insecticides against pear psylla in ‘Sekel’pear trees applied with the pesticide delivery system of the presentinvention is examined and compared to conventional insecticides.

Four ‘Sekel’ pear trees infested with pear psylla nymphs are eachtreated with PM (3% weight by volume) and water; PM (3% weight byvolume), water, and Dimilin at 4 oz Al/a and 8 oz Al/a (an insect growthregulator) (Active Ingredient per acre); PM (3% weight by volume),water, and Agri-Mek at 2.5 oz Al/a and 5 oz Al/a (a neurotoxininsecticide); water and Dimilin at 4 oz Al/a and 8 oz Al/a; water andAgri-Mek at 2.5 oz Al/a and 5 oz Al/a; or untreated. Four infestedleaves are taken from each treatment of each tree to assess live anddead psylla nymphs before treatments are applied and 14 days aftertreatment. The % mortality is reported in Table 2.

TABLE 2 Treatment % Mortality untreated 5 PM 33 A-M-2.5 31 A-M-5 28Dimilin-4 45 Dimilin-8 26 PM/A-M-2.5 32 PM/A-M-5 50 PM/Dimilin-4 62PM/Dimilin-8 68

Table 1 shows that the blossom infect rate of apple trees by Erwiniaamylovora is markedly lower when a pesticide delivery system inaccordance with the present invention is employed. That is, when thebactericide, microbial bactericide, or antibiotic is combined withparticulate material as described herein (in accordance with the presentinvention), the rates of infection is reduced compared using thebactericide, microbial bactericide, or antibiotic without particulatematerial. Table 2 shows similar results. In particular, Table 2 shows anincreased mortality rate of nymphs on pear trees when using aninsecticide combined with particulate material in accordance with thepresent invention compared to using the insecticide alone or withoutparticulate material.

While the invention has been explained in relation to its preferredembodiments, it is to be understood that various modifications thereofwill become apparent to those skilled in the art upon reading thespecification. Therefore, it is to be understood that the inventiondisclosed herein is intended to cover such modifications as fall withinthe scope of the appended claims.

What is claimed is:
 1. A method of delivering a pest control agent to atarget organism, comprising: applying to at least a portion of a surfaceof a substrate selected from a plant, a man-made structure, and storedgrain, an effective amount of finely divided particulate material atleast partially coated with the pest control agent, the particulatematerial comprising from about 25% to about 100% by weight of a heattreated particulate material, the heat treated particulate materialheated to a temperature from about 400° C. to about 1,200° C. for a timefrom about 10 seconds to about 24 hours, wherein the partially coatedfinely divided particulate material as applied permits an exchange ofgases on the surface of the substrate and the partially coated finelydivided particulate material forms a continuous film over the portion ofthe substrate surface to which it is applied, and a maximum average sizeof openings in the continuous film is less than about 100 μm.
 2. Themethod of claim 1, wherein the film of partially coated finely dividedparticulate material has a thickness from about 1 μm to about 1,000 μm.3. The method of claim 1, wherein the plant is selected from the groupconsisting of fruits, vegetables, trees, flowers, grasses, roots, seedsand landscape and ornamental plants.
 4. The method of claim 1, whereinat least 90% by weight of the finely divided non-absorbent particulatematerial has a particle size distribution wherein at least 90% by weightof the particulate material has a particle size under about 3 microns.5. The method of claim 1, wherein the pest control agent comprises atleast one of an insecticide, an acaracide, a fungicide, a bactericide, aherbicide, an antibiotic, an antimicrobial, a nemacide, a rodenticide,an entomopathogen, a phermone, a chemosterilant, a virus, an attractant,a plant growth regulator, an insect growth regulator, a repellent, aplant nutrient, and a phagostimulent.
 6. The method of claim 1, whereinthe target organism comprises at least one of a bacteria, a fungus, aworm, an insect, an arachnid, a bird, an unwanted plant, and a rodent.7. The method of claim 1, wherein the finely divided particulatematerial further comprises at least one of calcium carbonate, talc,hydrous kaolin, bentonites, clays, pyrophyllite, silica, feldspar, sand,quartz, chalk, limestone, precipitated calcium carbonate, diatomaceousearth, barytes, aluminum trihydrate, pyrogenic silica, and titaniumdioxide.
 8. The method of claim 1, wherein the partially coated finelydivided particulate material is applied by spraying in a slurry form. 9.The method of claim 1, wherein the method of delivering a pest controlagent to a target organism is performed without diminishingphotosynthesis of the plant.
 10. The method of claim 5, wherein theplant nutrient comprises nitrogen, magnesium, calcium, boron, potassium,copper, iron, phosphorus, manganese, and zinc.
 11. The method of claim1, wherein the continuous film comprises from about 0.05% to about 10%by weight of the pest control agent and from about 90% to about 99.95%by weight of the heat treated particulate material.
 12. The method ofclaim 1, wherein the heat treated particulate material comprisescalcined kaolin.
 13. A method of delivering a pest control agent to atarget organism, comprising: applying to at least a portion of a surfaceof a substrate selected from a plant, a man-made structure, and storedgrain, an effective amount of finely divided particulate material atleast partially coated with the pest control agent, the particulatematerial comprising from about 25% to about 100% by weight of a heattreated particulate material, the heat treated particulate materialcomprising one or more selected from the group consisting of calcinedcalcium carbonate, calcined talc, calcined kaolin, metakaolin, calcinedbentonites, calcined pyrophyllite, calcined feldspar, calcined chalk,calcined limestone, calcined precipitated calcium carbonate, calcinedbarytes, calcined aluminum trihydrate, and calcined titanium dioxide,wherein the partially coated finely divided particulate material asapplied permits an exchange of gases on the surface of the substrate andthe partially coated finely divided particulate material forms acontinuous film over the portion of the substrate surface to which it isapplied, and a maximum average size of openings in the continuous filmis less than about 100 μm, and the continuous film comprises from about0.01% to about 30% by weight of the pest control agent and from about70% to about 99.99% by weight of the heat treated particulate material.14. The method of claim 13, wherein the heat treated particulatematerial comprises calcined kaolin.
 15. A method of delivering aninsecticide to a target organism, comprising: applying to at least aportion of a surface of a substrate selected from a plant, a man-madestructure, and stored grain, an effective amount of finely dividedparticulate material at least partially coated with the insecticide, theparticulate material comprising from about 25% to about 100% by weightof a heat treated particulate material, the heat treated particulatematerial heated to a temperature from about 400° C. to about 1,200° C.for a time from about 10 seconds to about 24 hours, wherein thepartially coated finely divided particulate material as applied permitsan exchange of gases on the surface of the substrate, the partiallycoated finely divided particulate material forms a continuous film overthe portion of the substrate surface to which it is applied, and amaximum average size of openings in the continuous film is less thanabout 100 μm, and the continuous film comprises from about 0.01% toabout 30% by weight of the insecticide and from about 70% to about99.99% by weight of the heat treated particulate material.
 16. Themethod of claim 15, wherein the heat treated particulate material isheated to a temperature from about 500° C. to about 1,000° C. for a timefrom about 10 minutes to about 10 hours.
 17. The method of claim 15,wherein the heat treated particulate material comprises calcined kaolin.18. The method of claim 15, wherein the heat treated particulatematerial comprises at least one selected from the group consisting ofcalcined calcium carbonate, calcined talc, calcined kaolin, metakaolin,calcined bentonites, calcined pyrophyllite, calcined feldspar, calcinedchalk, calcined limestone, calcined precipitated calcium carbonate,calcined barytes, calcined aluminum trihydrate, and calcined titaniumdioxide.